Who Killed the Prosecutor and Why

Carlo a young photographer is making love with his girlfriend at the beach when he witnesses a murder being feebly staged to look like a car accident Carlo takes incriminating shots of the murderers the victim turns out to be the local public prosecutor and attempts to sell them to various interested parties including a gangster and a newspaper owner One of the murderers accomplices a lowlife criminal is gunned down by a blackgloved assassin while another is stabbed to death